Field of the Invention
The present invention relates to a position adjusting mechanism used for adjusting a position of a member to fix this member to another member, a drive transmission device, a printing apparatus, and a fastening method.
Description of the Related Art
There are drive transmission devices that include, for example, a belt member that transfers a drive force from a drive source to a driven member. Of the drive transmission devices, there is known a drive transmission device that has a tension adjusting mechanism configured to adjust tension for the belt member. In this type of tension adjusting mechanism, a retaining member for a tension roller which stretches the belt member, is fixed with a screw at a position where the tension of the belt member is equal to a desired tension.
At the time of tightening the screw, the area of a contacting surface between the retaining member and the screw in a direction crossing the tension adjusting direction may differ between the upstream side and the downstream side in the crossing direction, for example, due to a screw inserting hole being formed larger than the diameter of the screw for an adequate margin. As a result, the contacting pressure differs depending on contact portions between the retaining member and the screw. This generates a difference between a force acting in a direction in which the tension is weakened and a force acting in a direction in which the tension is strengthened, and the retaining member moves toward the tension adjusting direction, which perhaps changes the tension of the belt member.
In order to prevent this change in the tension, Japanese Patent Laid-Open No. 2013-40667 discloses a retaining member configured such that a portion of the bearing surface of a screw furthest from the rotating center of the screw in a direction crossing the tension adjusting direction is not brought into contact with the retaining member.
However, in the case of providing a portion where the retaining member and the screw are not brought into contact with each other as with the configuration disclosed in Japanese Patent Laid-Open No. 2013-40667, the area of the retaining surface (friction surface), where the screw is retained after the screw is tightened, narrows as compared with the case where the non-contacting portion is not provided, whereby the frictional force therebetween reduces. As a result, a relative displacement may occur between the retaining member and the screw in the case where a force occurs against the frictional force between the retaining member and the screw, for example, due to vibration of a device during operation or an impact occurring in the case where the apparatus is dropped, and this possibly leads to a change in the tension of the belt member or deformation of each member.
This problem, which the tension adjusting mechanism has, also exists in a position adjusting mechanism that: provides a portion where a member corresponding to the retaining member and the screw are not brought into contact with each other; adjusts the position of this member; fixes this member to another member; and maintains the member at a desired position. With the position adjusting mechanism as described above, the member may be displaced from the desired position in the case where the member receives force stronger than frictional force between the member and the screw after the member is fixed to another member with a screw.